Fire door



vF. W. DEAN.

FIRE DOOR.

APPLICATION FILED AUG-7, 1919.

1 ,408,867. I Patented Mar. 7,1922.

unrruo sm es FRANCIS W. DEAN, OF LEXINGTON, MASSACHUSETTS.

' FIRE noon.

Specification of Letters Patent.

Patented lllfar. 7, 1922.

Application filed August 7, 1919. Serial No. 315,923.

TouZZ whom. it may concern.

lie it-known that l, FRANCIS WV. DEAN, a citizen of the United States of America, a resident of Lexington, in the county of Middlesex, State of Massachusetts, have invent ed certain new and useful Improvements in Fire Doors, of which the following is a full, clear, and exact description, referencebeing had to the accompanying drawings, forming a part of this specification.

My invention relates to improvements in zi're'doors adapted for use on furnaces and the like, the object being to produce a draft receiving lire door whereby the draft is most effectively utilized to facilitate combustion of the fuel, and also to prevent burning away of the inside of the door and the in nor margin of the dead plate which lies adjacent to the fuel. To accomplish these results, the draft should be discharged di rectly into the bed of fuel, instead of being permitted to escape over the top of the fuel bed, and almost the entire area of the inner wall of the fire door should be exposed to thecooling action of all of the draft passing through the door. it is especially important to effectively utilize the draft as a means for cooling the lower margin of said inner wall.

Prior JO this invention, fire doors formed with, inner and outer walls have usually been provided with a large draft inlet near the center of the outer wall, and the inner wall has been perforated. at various points above andbelow the horizontal center line of the door, to provide numerous scattered dis charge openings for the draft. In these old fire doors, the draft,entering at the center of the outer wall of the door, strikes the perforated inner wall which serves as a baffle ordistributer, causing the air currents to spread in various directions so as to escape through the numerous perforations above and below the horizontal center line of the door. However, most of the air will escape through the perforations near the center of the door. It will be observed that substantially all of the draft will be discharged enti rely above the top of the bed of fuel in the furnace,; but the draft would be far more effective if it was discharged directly into the bed of fuel. Furthermore, actual experience has shown that the liners, or inner walls, of the old type of fire door are soon destroyed by the heat of the furnace, and the dead plate forming a threshhold for the fire door is likewise burned by the intense heat of the furnace. It is therefore apparent that the draft passing through the ordinary firedoors does not effectively cool either the inner wall of the door or the dead plate.

In the preferred form of the invention, the lire door has an outer wall provided with an elongated horizontal draft'inlet at'its top margin, and the inner wall is separated from said outer wall to provide a clown-duct for all of the draft entering through said top margin] A discharge port forthe draft is formed at the lower margin of the inner wall The door is otherwise closed to prevent frec aomission or escapeof draft at any other points. All of the incoming draft must, therefore, pass downwardly along the inner wall of thedoor, so approximately the entire area of the inner wall is exposed to the cooling action of all of the. draft. After being preheated by passing from the top to the bottom of the inner wall, all of the draft, passing from the lower margin of the door, is forcibly discharged'over the dead plate and directly into the bed of fuel. The draft is thus utilized to cool the inside of the door and the dca d plate, and then discharged into the fuel bed where it will connningle directly with the solid fuel undergoing combustion.

Fig. I is a vertical section of a portion of a furnace, illustrating a fire doonconstructed in accordance with this invention.

Fig. II is a front elevation of the door and the frame whereby it is supported.

A designates the front wall of a furnace provided with a fuel-receiving opening 1 adjacent to a grate 2, on which the fuel is supportedp 8 designates the dead plate at the bottom of the opening 1. l

A door frame B, secured to the front wall of the furnace, extends around the opening 1, said door frame having a wide top flange 4, a narrow bottom flange 5 and side flanges 6 provided with inclined edges which extend from the top flange to the bottom flange.

Inclined ribs 7 are formed on the side.

flanges to limit the outward movement of the fire door.

The door I have shown to illustrate the preferred form of the invention comprises a rectangular outer wall. 8 located between the side flanges 6 on the door frame and extending from thertop flanges to the bottom flange 5, the upper edge ofsaid outer wall 8 being in front of the topflange. The upper portion of the outer wall 1s provided with an elongated horizontal draft inlet 9, which extends approximately from one side of the door to the other. An inward wall or liner 10 is separated from the outer wall to form a down-duct 11 for the draft entering through the inlet 9. The lower edge of the inner wall 10 is higher than the lower edge of the outer wall to form an elongated horizontal discharge port for the draft.- The down-duct 11 and its discharge port extend entirely across the interior of the door, said duct beingopen at the bottom to permit the incoming draft. to pass freely from the bottom of the door.

A damper 12, pivoted at 13, is arranged inside of thedoor to control the flow of'air' g to arms 19 fixed to the trunnions 16. When the parts occupy the positions shown in the drawings, the counterweight tends to retain the door in; its closed position.

The means for connecting the inner wall 10 of the fire door to the outer wall, preferably includes bolts 20 having heads 21, which lie in pockets formed at the ends of separating lugs 22 on the inner wall 10. These lugs separate the inner wall from the outer Wall; I

"charge opening at the lower edge of the To prevent undue heating of the bolt heads 21 which lie adjacent to the fire, very small holes may be drilled through the lugs 22 on the inner wall '10. These res ricted holes; or ports allow a very small proportion of the draft to escape at the bolt heads. 21', butthe leakage is so slight that it' does not materially. impair the efliciency of thecurrent of air escaping through the disinner wall 10.

All of the draft pa'ssing'through the fire doorenters at the elongated inlet 9 and passes into the. top of the down-duct '11,

whereby' it is conducted to the discharge 7 opening at the lower edgeof the inner wall.

The; draft is thus discharged over the dead plate 3, and it passes directly to the bed of fuelsupported on the grate 2. It is an advantage to. discharge the draft directly into the solid fuel on the grate. Another important advantage lies inthe discharge of all of the draft onto the dead plate 3, so as to maintain the. latter in a relatively cool condition,"thereby protecting it from the destructive effects of the intense heat at the adjacent bodyof fuel. It is likewise important to prevent burning or destructive heating of the inner wall 10 which forms A part of the fire door, and this is accomplished by causing all of the draft to pass downwardly from the top h bottom of said inlet and toalso prevent free escape of air above said discharge'opening.

I claim: I

1. A. fire door having an outer wall provided with a draft inlet, an inner wall separated from said outer wall to provide a down-duct for the draft entering through said inlet, a discharge port for the draft being formed at the lower margin of said inner wall, and fastening means whereby said inner wall is secured to said outer wall, the inner end of said fastening means being secured at said inner wall, and a restricted outlet for the draft being formed in said inner wall at. said inner end of the fastening means forthe purpose set forth.

i A fire'door having an outerwall provided at its upper margin with an elongated horizontal slot forming a draft inlet which extends approximately from one side of the door to the other, an inner wall separated from saidouter wall to form a down-duct for the draft enteringsaid draft inlet at the upper margin, the lower edge of said inner I wall being higher than the lower edge of said outer wall so as to form an elongated horizontal discharge port for the draft, the walls of the fire door being otherwise closed to prevent the admission of air below said draft inlet and to also prevent free'escape of air above said discharge port, spacing lugs between said inner and outer walls,

imperforate fastening means extending through said spacing lugs and inner and outer walls and securing them together, each of said lugs and the inner wall'having restricted draft outlets formed therein whereby the'fastening means are cooled, a damper located between said walls and at said draft inlet tocontrol the admission ofair to said down-duct, a door frame, and a pivotal sup- In testimony that I claim the foregoing l hereunto affix my signature.

FRANCIS W; DEAN. 

